EASB

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EMERGENCY 

ALERT SERVICE BULLETIN 

SUBJECT: ROTORS – MGB oil cooling fan

 Checking play between a fan blade and the guide vane bearing housing 

 ATA: 65 

AIRCRAFT Version(s) 

CONCERNED NUMBER 

Civil Military

SA330 05.96 J Ba, Ca, Ea, L, Jm, S1, Sm 

Revision No. Date of issue 

Revision 0 2010-07-12 

Summary: 

Check for a minimum play of 0.2 mm between a fan blade and the guide vane bearing housing 

This check can be performed using a locally manufactured tool. If the min. play is not complied with, replace the 

two bearings of the fan rotor shaft.

Compliance: 

EUROCOPTER renders compliance with this ALERT SERVICE BULLETIN mandatory. 

For the attention of 
 EASB

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1. PLANNING INFORMATION 

1.A. EFFECTIVITY 

1.A.1. Helicopters/installed equipment

On the Main Gearbox (MGB) fan assembly. 

1.A.2. Non-installed equipment

Not applicable. 

1.B. ASSOCIATED REQUIREMENTS 

Not applicable. 

1.C. REASON

EUROCOPTER has been informed of a new case of serious deterioration of the MGB oil cooling fan 

assembly. 

The fan rotor burst, due to its interference with the upper area of the guide vane bearing housing, and some 

rotor blades have impacted the MGB compartment environment and caused puncture holes in the 

transmission deck. However, the hydraulic pipes and flight controls located nearby were not affected by 

impacts. 

Such interference is due to the internal degradation of the fan bearings. 

After a previous case, EUROCOPTER issued a Service Letter (LS) No. 1912-65-08 on August 12, 2008, to 

inform of the modification of the fan maintenance consisting in checking for contact between the fan rotor and 

the guide vane bearing during the ALF inspection. 

This additional maintenance set forth in this Service Letter and introduced late in the documentation 

(currently being issued), is canceled when the mandatory check of play, introduced by this ALERT SERVICE 

BULLETIN, is carried out. 

EUROCOPTER renders compliance with the instructions in this ALERT SERVICE BULLETIN mandatory to 

enable the early discovery of the potential degradation of the fan rotor bearings, by checking the play 

between a fan blade and the guide vane bearing. 

1.D. DESCRIPTION 

- Check the play between a blade and the guide vane bearing housing: 

 . If the min. play is not complied with, replace the two bearings of the fan rotor shaft.
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1.E. COMPLIANCE

1.E.1. Compliance at the works

Not applicable. 

1.E.2. Compliance in service

Helicopters/installed equipment: 

Comply with paragraph 3. within 10 flighing hours following receipt of this ALERT SERVICE BULLETIN, 

issued on the date indicated at the foot of the page. 

Then, 

Comply with paragraph 3. at intervals not exceeding 10 flying hours. 

 Non-installed equipment: 

Not applicable. 

1.F. APPROVAL

 Approval of modifications: 

Not applicable. 

 Approval of this document: 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved on 

12/07/2010 under the authority of EASA Design Organisation Approval No. 21J.056 for civil version 

helicopters subject to an Airworthiness Certificate. 

The technical information contained in this ALERT SERVICE BULLETIN Revision 0 was approved on 

12/07/2010 under the registered letter Ref. 346621 DGA/DT/CEP/ASA for French government helicopters.

The technical information contained in Revision 0 of this ALERT SERVICE BULLETIN was approved on 

12/07/2010 by the EUROCOPTER Airworthiness department for export military version helicopters. 
 EASB

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1.G. MANPOWER

Qualification: 

1 Mechanical engineering technician. 

Time for the operation: 

- Approximately 2 hours for the first check of the play (local manufacture of the tool included), 

Then, approximately 10 minutes for all the other checks of the play. 

- Approximately 6 hours to replace the bearings. 

1.H. WEIGHT AND BALANCE

Not applicable. 

1.I. EFFECT ON ELECTRICAL LOADS

Not applicable. 

1.J. SOFTWARE MODIFICATION EMBODIMENT RECORD

Not applicable. 

1.K. REFERENCES 

- Maintenance Manual (MDE) Work Card: 65.33.402. 

- MAT 8582 Work Card: 321PA 

1.L. OTHER DOCUMENTS AFFECTED 

Not applicable. 

1.M. INTERCHANGEABILITY OR MIXABILITY OF PARTS

Not applicable. 
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2. MATERIAL INFORMATION 

2.A. MATERIAL: PRICE - AVAILABILITY - PROCUREMENT

Price: 

For any information concerning the cost of the kits and/or components for the modifications, for the tools, or 

for assistance, contact the EUROCOPTER Network Sales and Customer Service Department. 

Availability: 

The kits, components or tools are delivered on the operator's order. 

Procurement: 

Order the required quantity (unless otherwise specified) 

from 

EUROCOPTER 

Etablissement de Marignane 

Direction Ventes et Relations Client 

ECR 

13725 MARIGNANE CEDEX 

FRANCE 

NOTE 1 

For ALERT SERVICE BULLETINS, order by: 

Telex: HELICOP 410 969F. 

Fax: +33 (0)4.42.85.99.96 

NOTE 2

On the purchase order, please specify the mode of transport, the 

destination and the serial numbers of the helicopters to be odified. 

The consumable materials listed in this ALERT SERVICE BULLETIN and in the referenced documents can 

be ordered from: 

INTERTURBINE AVIATION LOGISTICS, 

Website: http://www.interturbine.com

Telephone : +49.41.91.809.300 

AOG : +49.41.91.809.444 

2.B. INFORMATION CONCERNING INDUSTRIAL SUPPORT

EUROCOPTER remains at your disposal for any further information or support you may require to comply 

with the instructions given in this ALERT SERVICE BULLETIN; please contact the EUROCOPTER 

Customer Service Technical Support Department: 

Phone: +33 (0)4.42.85.99.67 

Fax: +33 (0)4.42.85.99.66 

Email: DynComp.Technical-Support@eurocopter.com
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2.C. MATERIAL REQUIRED FOR EACH HELICOPTER/ENGINE/COMPONENT 

 Kits or components to be ordered for one helicopter or one assembly: 

Description Qty Material P/N Item 

Bearings 2 704A33651114 1 

 

 Tools: 

Refer to the Work Cards referenced in this ALERT SERVICE BULLETIN. 

2.D. MATERIAL TO BE RETURNED 

Not applicable. 
 EASB

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3. ACCOMPLISHMENT INSTRUCTIONS 

3.A. GENERAL 

Refer to the general instructions given in MDE Work Card 65.00.301 or MAT 8582 Work Card 320A. 

3.B. OPERATIONAL PROCEDURE 

3.B.1. Preliminary steps

Open the sliding cowling. 

3.B.2. Procedure

As per Figures 1 and 2

- Using a 0.2 mm (0.008 inches) feeler gauge attached to a locally manufactured rigid rod, check for a 

minimum play of 0.2 mm between a fan rotor blade (a) and the upper section of the guide vane bearing 

housing (b): 

. Insert the tool through the fan grid (c) to check the play at the bottom of the guide vane bearing between 

a blade (a) and the upper section of the guide vane bearing housing (b). 

NOTE

Play must be checked over the entire width of a fan blade. 

In order to be inserted through the fan grid, the rigid rod equipped 

with the feeler gauge, must have a maximum width of 12 mm, and 

its length must be equal to 150 mm minimum. 

Interpretation of the results:

a) If the feeler gauge can be inserted between the blade and the housing (play greater than or equal 

to 0.2 mm):

- Leave as is. 

- Return the helicopter to flight configuration in accordance with paragraph 3.B.3. 

b) If the feeler gauge cannot be inserted between the blade and the housing (play less than 0.2 mm):

As per Figure 3

- Remove the two bearings (d) of the fan rotor shaft as per MDE Work Card 65.33.402 or MAT8582 

Work Card 321PA. 

- Install the two new bearings (1) as per MDE Work Card 65.33.402 or MAT8582 Work Card 321PA. 

- Return the helicopter to flight configuration in accordance with paragraph 3.B.3. 

3.B.3. Final steps

- Close the sliding cowling. 

- Resume flights. 
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DETAIL A

0.2 mm min. play over the 

entire width of the blade 

a 

b 

c 

Figure 1 

Area to be checked 

A 

c 

b Area to be b 

checked 
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Figure 2 

c 

0.2 mm min. play over the 

entire width of the blade

Guide vane bearing housing 

c 

a 

b 
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Figure 3 

d 

1 

d 

1 
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3.C. IDENTIFICATION 

Identification of this document: 

Record first compliance with this ALERT SERVICE BULLETIN in the log card of the fan assembly. 

3.D. OPERATING AND MAINTENANCE INSTRUCTIONS

Not applicable.